Contralateral internal mammary node invasion in breast cancer: lymphoscintigraphic data

Contralateral internal mammary (IM) node invasion has been analyzed in 1025 patients where the two IM chains have been investigated by lymphoscintigraphy. Contralateral IM lymphoscintigrams (LySc) were classified as abnormal (nodes involved by metastatic cancer) in 153 cases (or 15.6% of the population) and this included one-third of the cases with homolateral IMLySc abnormalities (114/318). Overall, patients with bilateral abnormalities on IMLySc (Grp A) had a similar survival to those with homolateral abnormal IMLySc (Grp B). However, when other prognostic variables were taken into account and two matched groups were obtained, patients with bilateral internal mammary node involvement had a highest incidence of clinically evident systemic metastatic disease than patients with homolateral IM involvement. Contralateral IM nodes are invaded in one-third of the cases with homolateral IM node invasion. These patients may have a prognosis worse than those with only homolateral IM disease.